Blasting cap



April 14, 1931. H. E. NASH ET AL BLASTING CAP Filed July 17. 1950 l m I M/VE/V70RJ Leon fi ufiacacl Weary E. Was/z Patented Apr. 14, 1931 UNITED STATES PATENT OFFICE HENRY E. NASH AND LEON W. BABCOCK, OF KENVIL, NEW JERSEY, ASSIGNORS TO HERCULES POWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF IDELAWARE BLASTING oar Application filed July 17, 1930. Serial No. 468,542.

Our invention relates to an improvement in blasting caps such as are used in the firing of commercial explosives.

Blastiillig caps as at present produced are largely e ective and few failures are encountered. However, where a cap fails to fire, it will be present in blasted down material and will, due to its very substantial power, be a distinct menace inthe subsequent use of the material. More particularly, where caps fail in connection with the mining of coal in which they are very largely used, the presence of a live cap in coal shipped to a consumer is likely to result in extensive damage, if not personal injury, when the coal is used.

Now, it is the object of our invention to provide a'bla/sting cap so constructed that if it fail, for example, in connection with the mining-of coal, its destruction will be insured 1n the preparation of the coal for shipment to the consumer by any of the several methods customarily used.

The blasting cap in accordance with our invention will, in general, comprise a casing adapted for firing through the medium of a fuse, electrically, or. in any other manner, and may contain any usual explosive charge I as, for example, fulminate, fulminate-chlorate, etc. Essentially the casing of the cap 'will be provided with an aperture normally closed by means of a closure of water soluble material, which will be normally non-hydroscopic and non-reactive with the material formin the casing and the material forming the" exp osive charge, as, for example, common alum (Ah S0 .K SO.,.24H O) ,sodium acetate (NaC H O .3H O) cane sugar, dextrose sugar, potassium bromide (KBr), gelatin, etc. 1

In operation, if the cap in accordance with our invention fail and be present, for exam: le, in coal removed from a mine, it will be estroyed when the coal is prepared for market by, for example, washing, jiggin flotation, or the like, since the water solu 1e closure for the aperture in the casing will be dissolved permitting water to wash out the explosive charge, which will be carried off to waste leaving at most merely the empty cas- 50 ing in the coal.

Having now indicated, in a general 'way, the nature and purpose of our invention, we will proceed/to a detailed description thereof with reference to the accompanying drawing in which we have illustrated a preferred embodiment and in which:

Figure 1 is a sectional view of a blasting cap of the type adapted to be fired by means of a fuse, embodying our invention.

Figure 2 is a sectional view of a cap similar to that shown' in Figure 1, but adapted for firing electrically.

Figure 3 is a sectional view of'a blasting cap adapted for firing electrically embodying a modification of our. invention.

Figure 4 is a sectionalview, partly broken away, of a blasting cap of the type adapted to be fired by means of a fuse embodying a further modification of our invention.

Figure 5 is a sectional view of a blasting cap similar to that shown in Figure 4 but adapted for firing electrically.

In the drawing a indicates a cap shell or casing, made of .any suitable or customary material, as, for example, copper. b indicates an explosive charge of any suitable or usual material or composition as, for example, fulminate, fulminate-chlorate mixture, etc. I

In connection with Figures 2, 3 and 5, c indicates lead wires adapted to be connected to a. source of electric current, as a blasting machine, and having their ends within the explosive charge connected by a fusible wire (1 by which the charge is fired, all as is customary. In Figures 2 and 5 e indicates the usual plugs and f indicates the usual fillin material by which the charge is protecte and sealed within the casing.

Referring now more particularly to Figures 1 and 2, the casing a is provided with an aperture in its bottom, the aperture being formed, for example, by punching out the bottom of the casing centrally so as to leave a. narrow flange g. In the bottom of the easing and closing the aperture therein is positioned a closure or plug it of a suitable water soluble material, as, for example, common alum. The closure 7). may be reformed and inserted in the casing, it may e melted and .100

.usual manner.

flowed in, or it may be pressed in, dependin upon convenience and the particular materia used. Above the closure h the ex losive charge is positioned, being inserted in any In the cap of Figure 1 the end of the casin is left open for the reception of an end 0% fuse, while the cap of Figure 2 is constructed for electrical firing.

Referring now to Figure 3 the casing 11 is of any usual type and the explosive charge I) is positioned therein as usual. On top of the explosive charge is placed a plug z of a suitable water soluble material as, for example, common alum and the casing is sealed by running into the end of the casing a mass of suitable water soluble material as, for example, common alum.

Referring now to Figures 4 and 5, the casing is provided with apertures k in its wall. For example, it may be slotted, and if desired, though not necessarily, it may be provided with an aperture in its bottom. Within the casing and closing the'apertures is a capsule Zmade from any suitable water soluble material as, for example, gelatin.

In practice, should a cap constructed, for example, as shown in Figures 1-3, fail and be present in blasted material, as, for example, coal, the water soluble material forming the closure h, or the plugi and seal 1' will be melted out when the coal is prepared with the use of water, as when it is washed, j i ged, or the like, and the water will effectively wash the explosive charge out of the casing, carrying it to waste.

In the case of the caps'shown in Figures 4 and 5, water will melt the gelatine capsule and the explosive charge will readily wash out of the casing.

It will now be noted that in accordance with our invention we provide a blasting cap so constructed that it will be readily destroyed if present in blasted material which is given a treatment with water.

It will be understood that our invention is adaptable to embodiment in blasting caps of various types and that structures involving various modifications of those herein described for illustrative purposes will be within the scope of our invention.

What we claim and desire to protect by Letters Patent is: Q

1. A blasting cap including in combination a casing provlded with an openin an explosive charge within the casing an a water soluble closure for said opening.

2. A blasting cap including in combination a metallic casing provided with an opening, an explosive charge within the casing adjacent said opening and a water soluble closure for said opening.

3. A blasting cap including in combination a tubular metallic casing, a mass of water soluble material within said casing, an aperture formed in said casing adjacent to and closed by said water soluble material, and an explosive charge ing adjacent to said water soluble material.

4. A blasting cap including in combination a tubular casing provided with an aperture in the bottom, a mass of water soluble material positioned within said casing and forming a closure for said aperture and an explosive charge superimposed on said water soluble material within said casing.

In testimony of which invention, we have hereunto set our hands, at Kenvil, N. J., on this 15th day of Jul 1930.

E. NASH.

H NRY LEON w. BABCOCK,

positioned within said cas 

